arXiv:2606.15950stat.MLcs.LG2026-06被引 2

针对非可交换结构数据,提出基于谱相似性的自适应预测区间方法。

Spectral Adaptive Conformal Prediction for Structured Non-Exchangeable Data

论文配图:Spectral Adaptive Conformal Prediction for Structured Non-Exchangeable Data
图 1 · 摘自论文原文
  • 利用局部谱相似性加权校准残差,构建更贴合当前测试点的预测区间。
  • 在多类真实时间序列数据上,覆盖率达95%以上且长期误覆盖率可控。
  • 适合处理具有周期性、频率缓慢变化的时间序列,如经济与金融数据。

同质化预测在数据可交换时能提供有限样本覆盖的预测区间。然而许多时间索引数据并非可交换:它们具有季节性、重复状态、频率变化等结构性依赖。本文提出一种简单利用结构的方法——谱适应性同质化预测。该方法通过局部谱相似性对校准残差进行加权,形成加权同质化分位数,并在线更新目标误覆盖水平。谱权重选择与当前测试点相关的校准残差,自适应更新则修正不确定性随时间变化导致的长期误覆盖率偏差。理论分析表明两部分均可控:给出近似覆盖界,将误差分解为谱不匹配项和有效样本量项;证明核谱加权不会使不匹配项劣于均匀加权;指出带宽为N^(-1/(d+2))时两项可平衡;并建立无独立性或平稳性假设下的无条件长期校准界。模拟实验涵盖重复状态与缓慢频率变化场景,四组真实数据(美欧月度、周度、日度序列)验证了该方法在多数情况下优于强基线,且一个可实时计算的有效样本量防护机制可检测并修复一次观测失败。

原文摘要 · Abstract (English)

Conformal prediction gives prediction intervals with finite-sample coverage when the data are exchangeable. Many time-indexed datasets are not exchangeable: they have seasons, recurring regimes, changing frequencies, or other forms of structured dependence. This paper studies a simple way to use that structure. We propose spectral adaptive conformal prediction, a method that forms weighted conformal quantiles using local spectral similarity and then updates the target miscoverage level online. The spectral weights choose calibration residuals that look relevant to the current test point. The adaptive update corrects the long-run miss rate when uncertainty changes over time. The theory makes both parts controllable. We give an approximate coverage bound that splits the error into a spectral mismatch term and an effective-sample-size term, prove that kernel spectral weighting never increases the mismatch term relative to uniform weighting, show that a bandwidth of order N^(-1/(d+2)) balances the two terms, and establish an unconditional long-run calibration bound for the adaptive update that holds for every sample path without independence or stationarity. Simulations with recurring regimes and slowly changing frequencies, together with four real-data examples spanning monthly, weekly, and daily U.S. and European series, show when the hybrid method improves on strong adaptive baselines and when it does not, and an effective-sample-size safeguard, computable at prediction time without outcomes, detects and repairs the one observed failure.

同质化预测时间序列谱分析覆盖保证

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